Reaction of dimethyloldihydroxyethyleneurea with p-dioxane and reaction product



nit s ABSTRACT OF THE DESCLOSURE The invention comprises the preparation of bis(dimethyloldihydroxyethyleneurea)-p-dioxane by reacting dimethyloldihydroxyethyleneurea with an excess of pdioxane. The product obtained is useful in modifying the breaking strength and crease recovery properties of cotton cellulosic textiles.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to the pre aration of non-hygroscopic N-methylol derivatives. More specifically, th s invention relates to the preparation of N-methylol derivatives which are stable to the loss of formaldehyde either in the solid state or in aqueous solution. This type of chemical reagent should find increasing commercial acceptance in the art of textile wash-and-wear applications since there is no liberation of formaldhyde upon handling or storage.

The main object of this invention is to stabilize certain N-methylol compounds by reacting them with p-dioxane and isolating the solid product obtained.

Another object of this invention is to apply the compounds obtained to cellulosic textile materials either in the presence or in the absence of an inorganic salt catalyst to impart wash-and-wear properties to the said cellulosic materials.

Other objects of the invention will become evident in the description of the investigative work which yielded the unexpected results presented in this specification.

To those skilled in this art, it is well known that urea derivatives react with formaldehyde to yield compounds which contain N-methylol(hydroxmethyl) groups. These materials react readily with cellulosic textiles in the presence of acidic catalysts to impart desirable wash-andwear properties to the finished fabric or garment. Prior to our invention the compounds used commercially to impart these desirable properties to cellulosics have not generally been isolated as solids. These have been available commercially only as aqueous solutions, and the N- methylol compounds have been prepared in situ by adding stoichiometric quantities of aqueous solutions of formaldehyde, usually as formalin, to aqueous solutions of the urea derivative. An acid-type catalyst is also sometimes added to the resulting commercial solution.

The commercial solutions, generally, lose formaldehyde by decomposition of the dissolved compound. Indeed, those N-methylol derivatives such as dimethylolethylene- States Patent Patented May 14, 1968 urea (DMEU) and dimethyloldihydroxyethyleneurea (DMDHEU) illustrated below lose formaldehyde even in the solid state due to their hygroscopic nature when exposed to the atmosphere. Such difi'iculties in the handling of these materials in their commercial application to cellulosic textiles can be eliminated by the use Of stable N-methylol compounds which are our invention. The preparation of these compounds is taught in the specification of this invention.

Generally, to prepare the stable derivatives, which are our invention, a compound of the following type is synthesized.

Dimethyloldihydroxyethyleneurea (DMDHEU) The compound, in which adjacent hydroxyl groups are located on a ring which has methylol groups attached to nitrogen atoms which are adjacent to a carbonyl group, is synthesized by reacting glyoxal, urea, and formalin in aqueous solution having a final pH of about from 7 to 8. The excess water is removed prior to reaction with pdioxane. For the product of this reaction we here suggest the chemical name bis(dimethyloldihydroxyethyleneurea)-p-dioxane, which we abbreviate as (DMDHEU -Dx The equation representing the formation of our product may be written as follows:

This chemical compound, which is pant of our invention, is a white powdery solid substance which melts at 115.5 to 116.5 C. It has been solubilized in water and in hot methanol, and it is probably soluble in many common organic solvents and mixtures of solvents used in commercial applications.

Chemical analyses of the product, which was isolated from the mixture in the reaction flask, indicate that the compound which is part of 'our invention contains one mole of p-dioxane for every two moles of the N-methylol o i t H20 CH2 L/ HO OH EFL-(LE H t HO(IIJN(H3N(|IOH O H Bis(dimethyloldihydroxyethylene-urea)p-dioxane Compounds which contain a ring and methylol groups but which do not have adjacent hydroxyl groups on the ring, such as DMEU, or compounds which do not have N-methylol groups but blocked ring hydroxyl groups, such as dimethyoxyethyleneurea (DMxEU) having the structure below 0 H l H i -t HCOH H H HC-Q O-CH H H DMxEU do not form such derivatives with p-dioxane. Nevertheless, dihydroxyethyleneurea (DHEU), which has the structure below I OH DHEU

does give a precipitate with p-diox ane. This indicates that ring hydroxyl groups and not N-methylol hydroxyl groups are .necessary in stabilizing such. N-methylol compounds to atmospheric moisture and loss of formaldehyde by reaction with p-dioxane.

The specific preparation of the stabilized compound is described in Example 1, below, and Example 2 describes the application of the (DMDHEU) -Dx to a cotton fabric. The stabilized compound may be applied to cellulosic textile materials from aqueous solutions with or without the assistance of a dissolved inorganic metal salt catalyst.

The impregnation of the cellulosic material is generally carried out in this manner. The material is immersed in an aqueous solution of the stabilized N-methylol compound of a molar concentration about from 0.22 to 0.50 without catalyst, imparting to the material wash-andwear properties. However, if time is of essence, or if a more wrinkle resistant product is sought, the same concentrations of the N-methylol compound are used with an added catalyst selected from the following: zinc chloride, zinc nitrate, hexahydratc, magnesium chloride hexahydrate, or magnesium nitrate hexahydrate. One of these inorganic metal salt catalysts is employed in the same solution at a concentration of about 0.03 mole per liter of solution.

Once the material has been impregnated with the compound, which is our invention, it must be dried at a temperature about from as low as room temperature (about 25 C.) to about 60 C. for about from 7 to 60 minutes,

the longer periods of time generally employed with the lower temperatures. The dry impregnated material is then submitted to a cure at about from to C. for about from 3 to 10 minutes, again the longer periods of time being employed with the lower temperatures.

The range of curing time indicated above reflects the situation when an acid catalyst is not present in the impregnating solution. For the process of this invention, it is not necessary to add a catalyst for the purpose of obtaining wrinkle resistant properties on the textile. However, as noted above, the use of a catalyst will improve wrinkle recovery properties and will reduce to some degree the time required for curing.

The materials to which the stabilized N-m'ethylol compound of our invention can be applied from aqueous solution include cotton, rayon, ramie, jute, flax, and the like, and in the case of cotton we have specifically applied our invention to the textile in the form of woven fabrics with satisfactory results. Those skilled in the art can readily visualize the extension of this application to other forms of textiles in the realm of cellulosic materials.

The following examples are presented to illustrate the invention, and since procedure and conditions can be varied by those skilled in the art, the examples are not set forth to establish any particular limits. The preparation of an N'methylol compound stabilized by reacting same with p-dioxane is described. Also, the application of the compound of our invention to cellulosic textiles is illustrated :by applying the same with and without an inorganic metal salt catalyst to cotton.

The treated cotton fabrics were submitted to selected standard tests as well as the other tests indicated here. Breaking strength determinations were done by the ASTM Method D39-40; dry wrinkle recovery determinations were done by the ASTM Method Dl295-60T; and wet wrinkle recovery determinations were done by the Lawrence and Phillips method described in American Dyestuff Reporter, volume 45, pp. 548-550, 561 (1956). Nitrogen values were obtained by the Kjeldahl method; metal analyses were done by ethylenediaminetetraacetic .acid titration; and formaldehyde values were done by the chromotropic acid method. The carbon, hydrogen, and nitrogen values for the (DMDHEU) -Dx of Example 1 were obtained by using standard microanalytical procedures.

Example 1 A non-hygroscopic N-methylol derivative was prepared as follows: To 197 parts of dihydroxyethyleneurea (DHEU), which, was prepared by modification of a procedure in British Patent 717,287, was added one part of calcium hydroxide. To this mixture was added 276 parts of a 36.3% formaldehyde solution with continuous automatic stirring for four hours. The DHEU was dissolved after the first hour of stirring, accompanied by a rise in temperature. Crushed Dry Ice was then introduced into the solution until the pH was adjusted to 7. The viscous solution was separated from the precipitated calcium carbonate by filtration, and was then placed in a vacuum desiccator. The liquid was kept in vacuo over P 0 for 9 days to remove excess water.

When p-dioxane, at room temperature, Was added to the viscous liquid, a white solid, which is the product of our invention, was immediately precipitated, and heat was liberated. The solid was filtered, washed with p-dioxane, at room temperature, and again filtered. It was then pulverized in a mortar, recrystallized from hot methanol, filtered, washed 3 times in methanol, and dried in vacuo over sodium hydroxide pellets.

A fraction of the product was taken and further desiccated over P 0 under pump vacuum for a few days. This product, which is our invention, was not hygroscopic, and was observed and recorded as being free of formaldehyde odor. The melting point of the product which is our invention is 1l5.5-116.5 (corn).

6 Analysis.-Calculated for C H N O C, 37.83; H, We claim: 6.35; N, 12.61. Found: C, 37.28; H, 6.44; N, 12.68. 1. A method comprising (a) reacting dimethyloldihydroxyethyleneurea with p- Example 2 dioxane at room temperature, the p-dioxane being 5 present in excess of the amount required to provide Eight samples of cotton printcloth (68 X 72 thread 1 mole f dioxane to 2 moles dimethYloldihy. count) weighing about from 9 to 10 grams each were droxyethyleneurea, and impregnated with the various bath solutions shown in b Separating the reaction product f o h unre. Table 1. Each sample was wetted and passed twice acted p-dioxane through a Laboratory Wfingef t0 Obtain pp a y 10 2. The reaction product produced by the method of 90% Wet weight pickup. Each sample was dried 1n a Claim 1 forced-air oven 7 minutes at about 60 C., and cured 3 minutes at about 160 C. Each sample was then washed in References Cited an automatic washer-dryer, with water containing a detergent (Triton X100), tumble-dried, and allowed to r UNITED F PATENTS equilibrate in the laboratory under normal conditions. 2,704,573 9/1956 RelPmtz et 260-3097 The treated samples were then submitted to select evalua- 3,029,164 4/1962 Sekl f 260-3097 tion, as described earlier in the specification, and the 3,209,010 9/1965 Gaghardl 260*3O9-7 desired and notable properties together with the results of chemical analyses were recorded, and are shown in JOHN RANDOLPH Pr'mary Examiner Table 1. NATALIE TROUSOF, Examiner.

TABLE 1.PROPERTIES OF COTTON PRINTCLO'IH TREATED WITH BIS(DIMETHYLOL- DIHYDROXYETHYLENEUREA)-P-DIOXANE (DMDHEU)g-Dx Composition of Bath Solutions Crease Wt. Gain, Metal, N, HCHO, Rot. Br. Recovery (DMDHEUh-Dx Catalyst Percent Percent Percent Percent Str. (W), Angles, olarity Used Percent degrees Dry Wet 0.22 2. 1 2 0.05 0. 47 0. 64 90 232 197 0.27 1. 1 2 0. 04 0. 40 0. 92 206 187 0. 2. 2 2 0. 04 0. 59 0. 49 95 221 190 0. 22 4. 8 0. 08 1. 15 1. 89 62 300 262 0. 22 3. 2 0. 11 1. 21 1. 77 41 317 288 0.22 3. 9 0.08 1.12 1. 57 309 268 0.22 IVIg(NOs)2- GHz 4.1 0. 08 1. 08 1. 63 52 301 261 0.27 Zn(NOs)zfiHzO 3. 4 0. 29 1. 19 2. 49 298 304 Untreated Control 2 0. 0B 0. 03 198 178 0. ()3 Molar Concentration. 2 Magnesium. 

